Editing Roller coaster (section)

=== Safety mechanisms and technology ===
A variety of safety mechanisms protect riders on roller coasters. 

==== Block system ====
Most large roller coasters have the ability to run two or more trains at once. 

The block system prevents these trains from colliding. In this system, the track is divided into two or more sections known as blocks. 

* Only one train is permitted in each block at any given time. 
* There is a section of track at the end of each block where a train can be stopped if necessary. 
** Examples include block brakes, the top of a lift hill (that can stop) and the station (train will not dispatch until the next block is clear).
* Sensors detect when a train passes so that the system's computer is aware of which blocks are occupied. If a train attempts to enter an occupied block, the stopping mechanisms in all blocks are engaged.{{citation needed|date=August 2023}}

==== Seat restraints ====
Seat restraints are used to ensure that riders stay in their seats throughout the ride.

===== Types of restraints =====
{| class="wikitable"
|+
!Type of restraint
!Description
!Pros
!Cons
!Sources
|-
|Over-the-shoulder
|Secures riders' torsos using a harness that is pulled down over the rider before the ride starts. 
|
* Can feel more secure for scared riders
|
* Can cause headbanging
* Can remove some airtime
* Can feel cramped or claustrophobic
|<ref>{{Cite web |title=Over-the-shoulder harness - Coasterpedia - The Amusement Ride Wiki |url=https://coasterpedia.net/wiki/Over-the-shoulder_harness |access-date=2025-05-10 |website=coasterpedia.net |language=en}}</ref>
|-
|Lap bar
|Secures riders' laps using either a bar that's pulled from in front of riders or pulled down from above like over-the-shoulder restraints
|
* More airtime
* No headbanging
* More open feel
|
* Can feel insecure or exposing for scared riders
* Can cause misconceptions that roller coasters with inversions that use lap bars are dangerous
|<ref>{{Cite web |title=Lap bar - Coasterpedia - The Amusement Ride Wiki |url=https://coasterpedia.net/wiki/Lap_bar |access-date=2025-05-10 |website=coasterpedia.net}}</ref>
|-
|Vest
|Similar to over-the-shoulder restraints but uses a vest pulled tightly on the rider's torso to secure them
|
* No headbanging
* Less bulky than over the shoulder restraints
|
* Tight
* Can remove airtime
|<ref>{{Cite web |title=Vest harness - Coasterpedia - The Amusement Ride Wiki |url=https://coasterpedia.net/wiki/Vest_harness |access-date=2025-05-10 |website=coasterpedia.net |language=en}}</ref>
|-
|Seatbelt
|Uses a belt across the rider's waist to secure them, or can be used as a fallback for other restraints
|
* Can be used in conjunction with other restraint types as a fall-back
* Can make scared riders feel more secure when used in conjunction with other restraints
* When used alone is very open and very unrestrictive
|
* Not suitable for most intense rollercoasters
|
|}

===== Restraint locking mechanisms =====
{| class="wikitable"
|+
!Locking mechanism
!Description
!Sources
|-
|Hydraulic
|Uses hydraulic piston and fluid to lock restraints.
When the restraint is pulled down, it forces liquid through a one-way valve. This liquid cannot return and thus the restraint stays closed. When the restraints are unlocked by the ride operator, an electrical signal is sent to another valve, which opens, allowing the fluid to return to the start position and letting the restraint rise.
|<ref>{{Cite book |last=Hoebiger |title=Personal restraint hydraulic lock LE |publisher=Hoebiger |year=2017 |location=Alabama |language=English}}</ref>
|-
|Ratcheting
|Uses a toothed gear and pawl to lock restraints. When the restraint is pulled down, the pawl clicks into the next tooth on the gear. The pawl cannot go in the opposite direction. When the restraint is unlocked by the ride operator, an electrical signal is sent to the pawl which moves it out of the way and lets the restraint go back up.
|<ref>{{Cite web |title=Griffin Schobel - Rollercoaster Restraint System (2019) |url=https://griffinschobel.com/rollercoaster-restraint-system |access-date=2022-05-02 |website=griffinschobel.com |language=en-US}}</ref>
|}
Restraints use proximity sensors to determine if they are locked. If not all of the restraints are locked, the train cannot leave the station.<ref>{{Cite book |last=Väisänen |first=Antti |title=Design of Roller Coasters |publisher=Aalto University School of Engineering |year=2018 |location=Espoo, Finland |pages=11 |language=English}}</ref>

==== Braking systems ====
Braking systems such as pivoting pawls are used on the bottom of the train and on the inclined lift hill. While the train goes up the lift hill, it is pulled by a chain. The pawl moves over bumps that are separated closely apart. In the event that the train ever becomes disconnected from the chain, the anti roll-back system will engage and it will fall back into the nearest downhill stop preventing the train from falling down the lift hill.<ref>{{Cite patent|number=US5715756A|title=Ride attraction anti-roll back system|gdate=1998-02-10|invent1=Weigand|invent2=Black|invent3=Drobnis|inventor1-first=Frank K.|inventor2-first=Alan|inventor3-first=Nick|url=https://patents.google.com/patent/US5715756A/en}}</ref>

==== Programmable logic controller ====
Another key to safety is the [[programmable logic controller]], an essential component of a roller coaster's computer system. Multiple controllers work together to detect faults associated with operation and automate decisions to engage various elements (e.g. lift, brakes, etc.). Periodic maintenance and visual inspection by ride engineers are also important to verify that structures and materials are within expected wear tolerances and functioning correctly. Effective operating procedures further enhance safety.<ref>[https://www.hse.gov.uk/pubns/books/hsg175.htm Fairgrounds and amusement parks: Guidance on safe practice]. ''Health and Safety Executive''. November 2017. Retrieved 7 March 2023.</ref>